Flush pendent sprinkler head



April 23, 1954 w. K. HODGMAN, JR 3,130,790

FLUSH PENDEINT SPRINKLER HEAD Filed Sept. 4, 1962 2 Sheets-Sheet 1 INVENTOR. WILLIS K. HODGMAN, JR

BY $1 1,? nyjflu f ATTOR NEYS April 28, 1964 w. K. HODGMAN, JR 3,130,790

FLUSH PENDENT SPRINKLER HEAD Filed Sept. 4, 1962 2 Sheets-Sheet 2 7 i 4a 3: 1 so 44 74 81 66 F8 42 4O 38 U 52 i I WILLIS K. HODGMAN,JR.

BYMMW ATTORNEYS United States Patent 3,130,790 FLUSH PENDENT SPRINKLER HEAD Willis K. Hodgrnan, Jr., Taunton, Mass., assignor to Hodgman Manufacturing Company, Inc., Taunton, Mass, a corporation of Massachusetts Filed Sept. 4, 1962, Ser. No. 221,183 3 Claims. (Cl. 169-40) This invention relates generally to automatic sprinkler systems for fire protection and more particularly to sprinkler heads of the pendent type which are intended for installation with the lowest portion thereof substantially flush with the ceiling.

In such fire protection systems heretofore known, it has been common to provide a wet pipe, or normally water filled, system with either upright or pendent sprinkler heads. Since a sprinkler system having upright sprinkler heads may be effectively drained if necessary, it has been common to prefer upright heads to pendent heads.

Pendent heads have been widely employed in two situations. First, pendent sprinkler heads may be mandatory where there is a limited amount of head-room available in the area in which the system is to be installed. If the main piping is located closely adjacent the ceiling of the room, it is frequently impossible to install upright sprinkler heads due to the height of such heads. Even if it were possible to physically install up right heads under such conditions, eflective water distribution would probably be severely hampered by the close location adjacent the ceiling.

Second, pendent sprinkler heads are required where it is desired to employ a false ceiling to conceal the sprinkler piping and for decorative or other purposes. In such installations, much of the piping for the sprinkler system is located between the false ceiling and the real ceiling or between the false ceiling and the floor of the story above, as the case may be.

With the increase in care being given to commercial appearances, coupled with the increased use of automatic sprinkler systems in retail and similar applications, such as schools, hospitals, libraries and other public buildings, a substantial problem has been encountered in providing an automatic sprinkler head which may be mounted substantially flush with a false ceiling while still having a minimum exposure below the ceiling needed to accomplish proper water distribution, and at the same time present an attractive appearance.

In sprinkler heads heretofore generally provided, a frame was employed in conjunction with the pipe orifice. A pair of toggle arms, offset from the center-line of the orifice, were used to apply a seating force between the frame and a cap positioned on the orifice. The toggle arms were held in position and tension maintained by use of a fusible link which was normally positioned gen erally parallel to the center-line of the orifice and hooked over the ends of the toggle arms.

In the construction of a fiush pendent sprinkler head it is important that the fusible link be positioned below the ceiling and outside of whatever containing structure may be located behind the ceiling. It had heretofore been believed that it was also necessary to provide a deflector positioned some distance below the ceiling in order to properly deflect the water issuing from the orifice, it being believed that at least a portion of the water should be redirected towards the ceiling. In order to provide as attractive a unit as possible, early attempts were made to provide flush pendent sprinkler heads with deflector structure which descended into a lowered position upon actuation of the head. Examples of such devices may be seen in the patents to Tyden, No. 2,389,333 and No. 2,389,334 and the patent to Rider 3,139,793 Patented Apr. 28, 1964 "ice No. 2,591,872. In these patents it will be noted that complicated trigger mechanisms and ejection devices are required to place the sprinkler head in operative condition.

It is a further object in any sprinkler head construction to provide a minimum of elements which must be discharged from the assembly before the sprinkler head may go into effective operation. The more elements there are to be discharged, the more likely is the possibility that the waterway will not be entirely free.

It has also more recently been determined that it is not only unnecessary to provide a deflector located some distance below the ceiling in order to rebound some of the water thereon, it is preferable to locate the deflector in such fashion as to break most of the water flow up into a spray which is deflected away from the ceiling in a downward and outward direction.

It is, accordingly, an object of my invention to provide a flush pendent sprinkler head having a minimum of parts to be discharged upon actuation and which may be mounted in such fashion as to extend a minimum distance below the ceiling line.

It is a further object of my invention to provide a sprinkler head construction in which the forces required to retain the cap on the orifice are absorbed by structural elements other than the frame used to position the defiector.

It is yet another object of my invention to provide a pendent type sprinkler head having a maximum of interchangeable parts for both lower production cost and greater ease in assembly.

In the practice of my invention, in a preferred embodiment thereof, I construct a flush pendent sprinkler head having a cast body with a central water dispensing orifice and a pair of arms straddling the orifice to position a deflector in direct line therewith. Hingedly mounted to the body and straddling the orifice approximately removed from the deflector supporting arms are a set of movable arms which extend below the deflector to receive a fusible link between them. A tension bar or bridge is also provided which engages protruding portions of the moveable arms at its bottom surface. A central compression screw extends from the upper surface of the tension bar and bears against the cap thereby maintaining the orifice in normally closed condition. The whole unit is provided for mounting behind the ceiling with the deflector and fusible link portions extending therebelow. An escutcheon plate is fitted to provide an attractive appearance.

In operation, the link fuses as is usual upon the proper degree of heat. The moveable arms fly apart releasing the tension bar. The cap is disloged by the water pres sure in the supply pipe and the link parts, tension bar, cap and valve gasket are discharged to provide an unobstructed waterway.

It is a feature of my invention that the fusible link is maintained substantially parallel to the under surface of the ceiling and spaced therefrom, thereby providing an attractive appearance.

It is a further feature of my invention that the tension bar is constructed in such fashion as to facilitate proper assembly. It is yet another feature of my invention that the deflector is rigidly mounted to the sprinkler head and is not required to descend prior to operation.

It is still a further feature of my invention that the moveable arms are not discharged upon actuation of the device, but hang in position to break up a portion of the water spray, thereby improving the distribution from the sprinkler head.

These and other objects and features of my invention will appear as the description proceeds with the aid of the accompanying drawings, in which:

FIG. 1 is a side view of a sprinkler head according to my invention, partially in section, showing the head in installed condition;

FIG. 2 is a fragmentary side view, partially in section, showing the action of the movable link receiving arms;

FIG. 3 is a view in perspective of the tension bar of my invention; and

FIG. 4 is a section taken on the line 44 of FIG. 1.

Referring to FIG. 1 of the drawings, a flush pendent sprinkler head is shown in installed condition, indicated generally at 10. The sprinkler head includes a body member 12, which in the preferred embodiment is cast of bronze. Referring to FIG. 2, it will be observed that the body 12 has an internal bore, indicated generally at 14, and is provided with external screw threads 16 at the upper extremity of the bore 14. The screw threads 16 are provided so that the body may be joined to the water supply piping (not shown) by any suitable means, such as a coupling 18 shown in FIG. 1.

The bore 14 terminates in a depending annular valve seat 26. A valve cap 22 is provided to close the water dispensing orifice defined by the seat 20. A copper valve gasket 24 is normally positioned between the cap 22 and the seat 20.

Integrally cast with the body 12 is a frame member 26 of generally U-shaped configuration. The frame 26 is integrally joined to the body 12 by the ends of its legs which are located at opposed sides of the water dispensing orifice. A boss 23 is formed on the frame 26 in substantial alignment with the center line of the bore 14 and valve seat 20. The boss 28 is tapped to receive a deflector or plate, indicated generally at 30. The deflector 30 is provided with a central upstanding screw threaded portion 31 which is received in the boss 28. The deflector 30 is disc shaped in configuration having a plurality of spaced radial fins 34 which as shown, extend outwardly and downwardly from the screw threaded portion 31. In the illustrated preferred embodiment, the fins 34 depend at an angle of approximately 9 to the horizontal. It will be understood that when the sprinkler head of my invention is installed in upright position a deflector of suitable conventional design for upright installation (not shown) will be substituted for the deflector 30.

It will be noted that the only function of the frame 26 is to support the deflector 3B in substantial alignment with the valve seat whereby the water flow will impinge upon the deflector fins 34 and be broken up into a plurality of small drops to form a fire extinguishing spray. In sprinkler head construction heretofore known it has been common to seat the valve cap on the valve seat by providing toggle arms between the cap and an aligned portion of a similar frame. It will be observed that the substantial stresses produced on the frame in such applications are not present in my construction wherein the frame need only have sufficient structural strength to properly position the deflector.

Spaced on the body 12 from the points at which the legs of the frame 26 join the body 12 are a pair of opposed sockets, indicated generally at 32. In the preferred embodiment, the sockets 32 are spaced approximately 90 from the legs of the frame 26. Each socket 32 comprises a pair of parallel, outwardly extending flanges 34. Each pair of flanges 34 is drilled to receive a pivot pin 36 therebetween. A lever arm 38 is hingedly suspended from one of the pins 36 and an identical lever arm 40 is hingedly suspended from the other pin 36. In practice, the lever arms 38 and 40 are identical in construction and in the preferred embodiment are stamped of brass with the same die. Since the lever arms 38 and 40 are of identical construction, although assembled somewhat differently as will be hereinafter described, only the lever arm 38 will be described in detail.

The lever arm 38 is formed with a substantially straight major portion 42 which extends from above the pivot pin 36 approximately three quarters of the length of the arm.

Approximately mid-way along the straight portion 42 of the arm 38 an inwardly projecting shoulder, indicated generally at 44, is formed. The shoulder 44 is provided at its inward-most edge with a rounded corner 46. An inclined flat face 48 extends from the corner 46 upwardly and outwardly to the straight portion 42. In the preferred embodiment, the inclined face 48 is approximately 10 to the horizontal.

The lower portion of the lever arm 38, beyond the straight portion 42, comprises a convoluted portion, indicated generally at 50, having a first section 52 which bends outwardly from the major portion 42 in order to clear the deflector 30 when in assembled condition. A second section 54 defines the lower end of the arm 38 and is curved in a reverse fashion to the portion 52 to form a hook element indicated generally at 56. The hook 56 is generally U-shaped in configuration and the open portion of the U faces outwardly from the longitudinal center line of the sprinkler head.

The hook portions 56 of the arms 38 and 40 are initially dimensioned such that in assembled condition a fusible link 58 may be positioned between them. Any suitable fusible link 58 may be used for the purpose, for example the fusible links disclosed in the patents to W. K. Hodgman, No. 1,520,750, and No. 1,539,311 and in my copending patent application Serial No. 859,413 filed on December 14, 1959, now Patent No. 3,061,016. A fusible link of the type described in the above listed patents and patent application generally comprises a pair of opposed link plates, each having a transverse channel. A key or fulcrum block is placed in the opposed channels and the link plates are joined together by a suitable fusible material. An aperture is formed in one end of each link plate and in assembled condition an aperture is thus located at each end of the fusible link. In the present invention the hook portions 56 of the lever arms 38 and 40 are positioned in engagement with the apertures thus provided in the link at their outward faces respectively. Since these apertures are located one in each of the link plates, which plates are disposed in face to face relationship, the respective horizontal center lines at the bearing points of the apertures are displaced approximately the thickness of one plate from each other. Since the arms 38 and 40 are stamped from the same die, it is necessary to pivot one of the arms higher in the body 12 than the other in order to maintain the link 58 parallel to the deflector 30 and the remaining horizontal portions of the sprinkler assembly. Where a flush pendent sprinkler head is provided it is important that an attractive appearance be produced. Since the link 58 is disposed generally parallel to the under surface of the ceiling in which the assembly is installed it is desirable to maximize the possibility of attractive appearance by constructing the sprinkler head in such fashion that the link will be as nearly parallel as possible. This can be easily accomplished by drilling the apertures indicated generally at 60 and 62 in the legs 38 and 40 respectively in such fashion as to compensate for the observed discrepancy in the horizontal center lines at the bearing points of the apertures in the link 58. As may be seen in FIG. 2, the lever arm 40 is engaged in the upper link plate and as a result, the aperture 62 is drilled somewhat further from the upper end of the arm 40 than is the aperture 60 in the lever arm 38 which is engaged by the lower link plate. In this fashion, the link 58 is positioned substantially parallel to the horizontal portions of the assembly.

The cap 22 is caused to seat on the valve seat 20 in assembled condition by a bridge member or tension bar 64. The tension bar 64 may be of any suitable configuration and in the preferred embodiment has the form of a truncated diamond. The tension bar 64 is tapped along its vertical center line, indicated generally at 66. A compression screw 68 is fitted in the tension bar 64 and is provided with a rounded end portion 70 which mates with a depressed central portion 72 of the cap 22. The tension bar 64 is initially dimensioned to bear against the inwardly projecting shoulders 44 formed on the lever arms 38 and 40 respectively.

Since the projecting shoulders of the lever arms 38 and 40, while disposed opposite each other, are at relatively different heights along the vertical axis of the sprinkler head as above described, it is necessary to make provision in the tension bar 64 for the relative difference in height between the two shoulder portions 44. This is accomplished by providing a first deeper cut, indicated generally at 74, for engagement with the shoulder 44 which is located on the lever arm 40. An inclined face 76 is provided in the cut 74 to cooperate with the inclined face 48 formed on the shoulder 44. A shallower cut, indicated generally at 78 is formed in the opposite end of the tension bar 64 having an inclined face 80 to cooperate with the inclined face 48 on the lever arm 38. The relative difference in height between the cut 74 and the cut 78 is the same relative difference as exists between the upper ends of the levers 38 and 40 and between the center lines of the bearing points at the apertures in the link plate 58.

The tension bar 64 in the preferred embodiment is initially manufactured with cuts 74 and 78 at both its upper and its lower surface. The relative position of the cuts 74 and 78 is reversed on the opposite sides of the bar 64 to provide maximum structural soundness while simultaneously providing for easy installation of the tension bar 64 regardless of the direction in which the compression screw 68 is inserted.

As seen in FIG. 2, the lower part of the tapped hole in the tension bar 64 is filled with solder 81 or some other sealing substance after final adjustment of the sprinkler head, as will be hereinafter described, in order to prevent subsequent tampering with the setting.

While the sprinkler head of the invention may be operated when assembled as above described, it is desirable in a flush pendent sprinkler head to provide structure whereby the head may be set in the ceiling in an attractive fashion. In the preferred embodiment, this is accomplished by providing an aluminum base 82, seen in FIGS. 1 and 4 which is fluted to receive the protruding portions of the body 12, namely the portions thereof which receive the legs of the frame 26 and which form the sockets 32. As seen in FIG. 4, the base 82 is thereby prevented from rotating any substantial amount with respect to the body 12. In order to secure the body against vertical movement with respect to the base 82 a metal washer or retainer nut 84 is fitted on the threaded portion 16 of the body 12 to bear against the upper surface of the base 82. A pair of opposed outwardly extending lugs 86 are also formed on the base 82 whereby it may be engaged by a suitable grooved wrench member (not shown) and rotated, thereby also rotating the body 12 to tighten the thread 16 into the coupling 18 or other pipe fitting into which the head is installed.

The lower external portion of the base 82 is provided with external screw threads 88 to which an adjustable ceiling plate, indicated generally at 90, having internal screw threads 92 may be fitted. The ceiling plate 90 includes a first substantially vertical portion 94 which extends from the base 82 to a point slightly below the lower surface of the ceiling. The portion 94 terminates at its lower end in an outwardly extending circumferential flange 96 which is substantially parallel to the under surface of the ceiling. The circumferential flange 96 itself terminates in an upwardly extending circumferential lip 98 which in assembled condition bears against the under surface of the ceiling.

The assembly and operation of my invention are as follows:

The deflector 30 is first secured in the boss 28 on the frame 26. The lever arms 38 and 40 are then swingably joined to the body 12 by the pins 36, and the arms 38 and 40 are moved sufficiently together to permit the link 58 to be engaged on the hook portions 56 thereof. Care should be taken to engage the link plate nearer the body 12 in the hook portion 56 formed on the arm 40 in order to maintain the link in a horizontal condition. The valve gasket 24 is placed on the valve seat 20 and the cap 22 is seated thereon to close the water dispensing orifice. The tension bar 64, fitted with the compression screw 68 is put in place. The compression screw 68 is initially positioned such that the tension bar 64 may be inserted between the lever arms 38 and 40 by disposing it initially at an inclined angle to the common plane thereof. Care is taken to seat the rounded end portion 70 of the compression screw 68 in the depression 72 formed in the center of the cap 22. The tension bar 64 is then positioned in general alignment with the arms 38 and 40. The deeper cut 74 in the tension bar 64 is aligned with the shoulder 44 on the arm 40 and the shallower cut 78 with the shoulder 44 on the arm 38. The compression screw 68 is then adjusted to move the tension bar 64 away from the cap and against the shoulders 44. The compression screw 68 is provided with a socket (not shown) for receiving a socket wrench to adjust the compression screw. When the tension bar 64 has been properly adjusted to seat the cap 22 firmly, and after pressure testing, a sealing compound, as for example solder 81, is placed in the socket portion of the compression screw and countersunk portion of the tapped hole in the tension bar 64 to render further adjustment thereof impossible. It has been observed that the cap 22 will be properly seated and in operational condition when a link tension of approximately 14 pounds is produced. It should be noted that in sprinkler heads heretofore known a higher link tension was required, for example, in the vicinity of 20 pounds. The structure of my invention permits the proper seating of the valve cap while producing a lower tension or pull on the link.

It will be noted that the structure of my invention thus provides an additional advantage over the prior art. Since a substantially lower link tension is required for proper, efficient operation of my sprinkler head, it is possible to employ a fusible link which is substantially more sensitive in operation than was heretofore possible. For example, a link having a fusing point of F. may be used with my new sprinkler head, whereas links rated at F., or above, were heretofore considered the most sensitive permissible due to the higher link tension heretofore required. Such higher rated links can, of course, also be satisfactorily used with my present invention.

The lower link tension above noted is produced since the closing pressure exerted by the tension bar 64 on the cap 22 is borne mainly by the shoulders 46 formed on the arms 38 and 40 rather than across the link itself. The tension bar 64 can be seen as a lever which is supported at both of its ends, having the load pressing downwardly at the central portion thereof.

When the sprinkler head of my invention is intended for a flush pendent application, the body 12 is fitted into the base 82 and secured thereto by the metal nut 84. The screw threaded end portion of the body 12 is then engaged in the supply piping by rotating the base 82 until a tight fit is attained. The ceiling plate is then engaged on the base 82 and is tightened up against the undersurface of the ceiling. As seen in FIG. 1, it will be noted that both the deflector 30 and the link 58 are disposed below the ceiling line, the remaining portions of the structure being generally obscured from view.

When the fusing temperature of the link has been achieved the fusible material retaining the link plates in assembled condition will melt and the link plates will fly apart in the usual fashion due to the tension exerted by the arms 38 and 40 across the link.

When the arms 38 and 40 are free from the restraining action of the link 58 they will also fly apart, pivoting on the pins 36. This action will be expedited due to water pressure and the inclined faces on the tension bar 64 which mate with the inclined faces on the shoulder 46. The position of the arms 38 and 40 after release is shown in dotted lines in FIG. 2. The tension bar 64, the cap 22 and the valve gasket 24 will be free to drop out of the assembly due to gravity and the water pressure in the bore 14. An unobstructed waterway will thus be produced allowing the water to impinge directly upon the deflector 30 and to be broken up into a spray as is desired. It will be noted that the only elements which need be discharged from my sprinkler head to create an unobstructed waterway are the link parts, tension bar, cap and valve gasket. It is not necessary to discharge the lever arms 38 and 40. It will be noted that this is a distinct advantage in providing against the possibility of an incomplete displacement of these parts which would result in an interference with the discharge of water.

It should also be noted that a distinct advantage in operation is achieved by the structure of my invention. It is imperative in sprinkler head construction that the head operate in a quick, decisive fashion. In fact, one should be able to hear a distinct pop or crack" upon actuation of the head. By quick, forceful operation any accumulated sediment or other foreign matter on the moving surfaces of the head is promptly fractured and proper operation is assured.

In sprinkler heads heretofore generally known, the valve cap seating force is applied by use of a holding and releasing structure, including a fusible element, disposed between the valve cap and a suitable point on a cast frame similar to the frame 26, such as a boss or the end of a screw positioned in such a boss. Structural resiliency is thus produced mainly by the spring action of the cast metal frame. In the sprinkler head disclosed herein the holding and releasing structure, which includes the fusible member, is independent of the frame and is so designed and constructed as to be inherently much more flexible and resilient while at the same time holding the valve cap seated firmly in place until fusing of the fusible member occurs. This flexibility and resiliency provides a substantially greater potential for throwing the components comprising the holding and releasing structure vigorously apart upon operation of the sprinkler head. This insures a quick, decisive operation of the sprinkler head upon fusing of the link and thereby constitutes a distinct advantage over the prior art construction.

During operation of the sprinkler it has further been observed that the lever arms 38 and 40 not only do not interfere with the proper operation of the device, but further act to break up the peripheral spray produced at the deflector 30, thereby achieving a better distribution of water.

While the sprinkler head of my invention has been described in the preferred embodiment as a flush pendent sprinkler head it will be understood that the structure of my invention may be equally well used in pendent systems which are not intended for flush installation as well as in standard upright systems.

It will also be understood that other modifications and variations of my structure may be made without departing from the invention. For example, the deflector holding frame need not be spaced 90 from the movable lever arms but may be positioned at any inclined angle thereto which would not interfere with the free operation of the lever arms. Also, the body of the head could be provided with internal rather than external screw threads.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an automatic sprinkler system, a sprinkler head comprising a body member having a water dispensing bore therethrough; means on said body member for connecting said bore to a Water supply system; a U-shaped frame mounted on said body member; a deflector mounted on said frame in alignment with said water dispensing bore; walls on said bore defining a valve seat at the end thereof; a valve cap dimensioned to seat on said valve seat; a pair of opposed arms; means including a pair of sockets each socket comprising a pair of outwardly extending flanges and a pivot pin disposed therebetween secured to said body member for swingably receiving one of said opposed arms, each of said arms being swingable outwardly from a first position generally parallel to the longitudinal axis of said bore to a second position spaced outwardly therefrom; a hook portion at the end of each of said arms for receiving a fusible link therebetween, said fusible link normally maintaining said arms in said first position; an inwardly projecting shoulder formed on each of said opposed arms; a tension bar; a pressure screw screwably received in said tension bar for positioning against the central portion of said valve cap; terminal portions on said tension bar for bearing against said shoulders formed on said opposed arms to apply a seating pressure to said central portion of said valve cap; a base; walls on said base for receiving said body member therein; and a ceiling plate removably secured to said base, said ceiling plate having a terminal portion adapted for close fitting engagement against the under surface of a ceiling.

2. In an automatic sprinkler system, a sprinkler head comprising a body member having a water dispensing bore therethrough, means on said body member for connecting said bore to a Water supply system, a frame mounted on said body member, a deflector mounted on said frame in alignment With said bore, walls on said bore defining a valve seat at the end thereof, a valve cap dimensioned to seat on said valve seat, a pair of opposed arms swingably secured to said body member and swingable outwardly from a first position generally parallel to the longitudinal axis of said bore to a second position spaced therefrom, a hook portion at the end of each of said arms for receiving a fusible link therebetween to maintain said arms in said first position, and means for maintaining said cap on said valve seat prior to fusing of said fusible link, said means comprising a tension bar, a pressure screw screwably received in the center of said tension bar for positioning against the center of said valve cap, and means including a shoulder on each of said swingable arms for hearing against said tension bar to cause said tension bar to apply a seating pressure on the center of said valve cap.

3. A sprinkler head as defined in claim 2 further characterized by said tension bar being provided with terminal portions for engagement with said swingable arms, inclined faces on said terminal portions and mating inclined faces on said arms.

References Cited in the file of this patent UNITED STATES PATENTS 325,982 Smith Sept. 8, 1885 531,120 Hibbard Dec. 18, 1894 1,371,043 MacGregor Mar. 8, 1921 1,885,226 Bronander Nov. 1, 1932 2,558,450 Martin June 26, 1951 2,768,696 Sherburne Oct. 30, 1956 2,871,953 Bray Feb. 3, 1959 

1. IN AN AUTOMATIC SPRINKLER SYSTEM, A SPRINKLER HEAD COMPRISING A BODY MEMBER HAVING A WATER DISPENSING BORE THERETHROUGH; MEANS ON SAID BODY MEMBER FOR CONNECTING SAID BORE TO A WATER SUPPLY SYSTEM; A U-SHAPED FRAME MOUNTED ON SAID BODY MEMBER; A DEFLECTOR MOUNTED ON SAID FRAME IN ALIGNMENT WITH SAID WATER DISPENSING BORE; WALLS ON SAID BORE DEFINING A VALVE SEAT AT THE END THEREOF; A VALVE CAP DIMENSIONED TO SEAT ON SAID VALVE SEAT; A PAIR OF OPPOSED ARMS; MEANS INCLUDING A PAIR OF SOCKETS EACH SOCKET COMPRISING A PAIR OF OUTWARDLY EXTENDING FLANGES AND A PIVOT PIN DISPOSED THEREBETWEEN SECURED TO SAID BODY MEMBER FOR SWINGABLY RECEIVING ONE OF SAID OPPOSED ARMS, EACH OF SAID ARMS BEING SWINGABLE OUTWARDLY FROM A FIRST POSITION GENERALLY PARALLEL TO THE LONGITUDINAL AXIS OF SAID BORE TO A SECOND POSITION SPACED OUTWARDLY THEREFROM; A HOOK PORTION AT THE END OF EACH OF SAID ARMS FOR RECEIVING A FUSIBLE LINK THEREBETWEEN, SAID FUSIBLE LINK NORMALLY MAINTAINING SAID ARMS IN SAID FIRST POSITION; AN INWARDLY PROJECTING SHOULDER FORMED ON EACH OF SAID OPPOSED ARMS; A TENSION BAR; A PRESSURE SCREW SCREWABLY RECEIVED IN SAID TENSION BAR FOR POSITIONING AGAINST THE CENTRAL PORTION OF SAID VALVE CAP; TERMINAL PORTIONS ON SAID TENSION BAR FOR BEARING AGAINST SAID SHOULDERS FORMED ON SAID OPPOSED ARMS TO APPLY A SEATING PRESSURE TO SAID CENTRAL PORTION OF SAID VALVE CAP; A BASE; WALLS ON SAID BASE FOR RECEIVING SAID BODY MEMBER THEREIN; AND A CEILING PLATE REMOVABLY SECURED TO SAID BASE, SAID CEILING PLATE HAVING A TERMINAL PORTION ADAPTED FOR CLOSE FITTING ENGAGEMENT AGAINST THE UNDER SURFACE OF A CEILING. 